84 4+3

You don't get the same cooling with an injector period... the only reason it works with a carb is because of the excess fuel present and vaporizing in the entire plenum. Any boosted DI car still needs an intercooler. It's not a flaw with injectors but rather an example of how wasteful carbs can be.

As for no difference, it all comes back to the whole flow theory... for the most part, your air that's being effected by the temperature is only at the wall and the rest of the volume isn't seeing anything. If its laminar. In turbulent flow you have better mixing and thus heat transfer... that's why intercoolers have a **** ton of tubes to mix it up instead of just being a big *** open box.

Tom400CFI

But it DOESN'T. Which is the precise reason OEM's have made the move to it....and made corresponding jumps in compression, boost or both. Ya "lecture" me on how gas evaporates...then don't even know it's effect in DI applications? As I said before, if gas is evap'ing in the cylinder in a DI engine (and it is), and it's evap'ing in the plenum w/a carb...then how can it not w/port inj....which is right in between both?? The fact is, it does evaporate, and proof of that is that we get good combustion and efficiency. If the gas stayed in a liquid state w/ port injection, you'd have incredibly poor combustion, or none at all.


Say what? So, if you tune the ECM on a port EFI system, to "run rich"...then you'll get the same cooling? Or if you jet a carb lean, you won't get it? Come on.

The fact is, the fuel evaporates in either case, and proof of that is that we get good combustion and efficiency. If the gas stayed in a liquid state w/ port injection, you'd have incredibly poor combustion, or none at all.



No. Intercoolers have a **** ton of tubes to increase the exposed surface area of the air to the aluminum. Turbulence is created by making the ID of each tube rough or textured.

Tom400CFI

Learning opportunity....



Watch from 0:00 to 3:06. Keep watching beyond if you can spare the time.

84 4+3

Roughness is one way, flow in the pipe running past the laminar regime is another. First thing we learned in heat transfer was not to make your heat exchanger so big as to drop the total flowrate out of the turbulent regime....

And I never said you don't get the cooling effect, I said it isn't the same.

Now that could also be wrong... I've been known to screw up a lot. That's why I'm going to school for engineering and am not presently an actual engineer.

So let me just leave it at this, does any of this **** actually make a meaningful difference? No. Probably not in any way shape or form.

Tom400CFI

I totally

sstonebreaker

But it DOES. The port is the restriction - else why port your heads to increase performance? If the intercooling doesn't occur until AFTER the restriction, then it doesn't do much good, does it?

Tom400CFI

Did you watch the video? No, ya didn't.

If you refuse to learn, no amount of factual info that I share, will help. FYI, "ports" aren't the only restriction in an engine.

sstonebreaker

Yeah, I did. At 4:30, he mentioned direct injection as maximizing the cooling effect within the cylinder itself. Which is too late to get more air into the cylinder. By cooling the air before it enters the port, you get a denser air charge going in. In other words, more molecules in the cylinder.

If you're so bent on proving someone wrong that you refuse to learn...

Tom400CFI

[See Video, produced by an actual engineer]
When did we take a left hand turn?? Please give me a moment to catch up;Who knows why, but I thought that we were talking about cooling effect. Not "molecules of air in the cylinder". I made absolutely zero reference to "number of molecules"....and neither did you. Can you stay on track here? I said DI cools, (as part of a larger point that fuel cools regardless of where you mix it into the air) and you had to argue that point about DI cooling, with me. So, of the two of us, who is...

This has been a Closer Look!

sstonebreaker

You guys can argue theory theory theory all you want. I've done the epoxy mod in real life. There is benefit to cooling/not heating the intake air in the manifold plenum. In the case of a basically stock gen 2 LT1, about two tenths in the quarter mile. And the kicker is, it's real easy for anyone to test. All you need is a bag of ice at test-n-tune night.

Tom400CFI

Fair enough. I haven't tried it, so I'll take your word for it. Epoxy.

84 4+3

Ice is cheap enough, next time you're at the track why not see if there is a difference or not between runs? Then we can prove or disprove the theory in real world.

Mity2

back in my Mustang days, a lot of sixers(that's what we used to call those with V6) had ideas like that.
Run AC straight in to intake for cooler denser air, run leaf blower in to intake and so on...

got nice chuckle out me...

Tom400CFI

A couple things:
1. I don't doubt that ice works. I'm sure it helps. 2/10? IDK about that. Maybe.
2. I'm not sure that an insulated intake is the same as a COLD intake. Maybe.
3. I'd be more interested in TRAP, as trap tells the HP story.
4. My drag track just closed this pas fall. For good. No more drag track in SLC, until UMC hopefully (Fingers crossed!) builds one.
5.Engine Masters just did that test...on a dyno and picked up 5 hp on an 800 hp engine.

BUT...if we get a drag track here again, I'll try it.

84 4+3

I know your pain, they closed englishtown on us 2 years ago. Sad day.

Tom400CFI

Thanks. It's a mixed bag. I'm totally bummed b/c I love drag tracking my car.

OTOH....it was the WORST RUN, most frustrating frickin' track I've ever been to. The place was a mind-****, waste of time, every time I went. So 1/2 of me is glad they're gone.

RMR SUCKED...DONG


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